DOI: 10.36347/sjet.2022.v10i07.006

Pages: 161-169

In this paper, density functional theory (DFT) was applied to study the isomerization process and fragmentation mechanism of deprotonated β-alanine ions ([β-Ala–H]–) at B3LYP/6-311++G(2df,2pd) level. The potential energy profiles of the [β-Ala–H]– in isomerization, H2O- and NH3-loss reaction pathways were plotted using relative to analyze preferred dissociation pathways and the structure of the resulting molecular ion products. In addition, the effect of temperature on reaction pathways and dissociative products were also investigated. The results show that a2 structure is the most stable configuration of [β-Ala–H]–, and the reaction barrier required for hydrogen transfer (47.76 ~ 54.02 kcal•mol-1) is higher during isomerization. Path 10 (ΔG≠ = 50.77 kcal•mol-1) is the dominant pathway of all the NH3-loss reaction, and the corresponding product p3 is also the dominant product in the deamination products. Path 1 is the dominant pathway in H2O-loss reaction. Meanwhile, temperature has no effect on dehydration and deamination reaction mechanism.